IRISH couples are most likely to fall out between 11am and noon on Christmas Day, according to leading relationship therapists.
Parents are at their most stressed in that hour because they feel exhausted and are likely to be busy juggling the preparation of the Christmas dinner, entertaining visiting family members and attempting to assemble their children's new Christmas toys.
Tony Moore, a counsellor with Relationships Ireland, said the three-day period from Christmas Eve to St Stephen's Day is the most testing period for married couples.
And he said he has been advising those in rocky relationships since October on how to get through Christmas without breaking up.
He said: "Christmas can be pure hell for many couples, particularly those who aren't used to spending a lot of time in each other's company.
"There's a huge marketing hype around Christmas that creates an expectation that everything's going to be fantastic. But in most households that's rarely the case."
Mr Moore said he devises what he calls a 'Christmas survival plan' for each couple he advises.
He said one of the biggest tips he gives to rowing partners is to go easy on the booze, which he said is far more likely to fuel rows.
He continued: "By about 11am, you'll already have been up a few hours, the kids will have opened the presents and the living room will be like a bomb site. Then the in-laws may be popping round and there's the Christmas dinner to prepare.
"But all this can be avoided with a bit of preparation and a clear head. And if the blokes help out with the Christmas dinner and tidying up, things will run a lot more smoothly."
Mr Moore has also reported a growing trend of affairs destroying relationships over the past 12 months.
He said cheating spouses are increasingly getting caught out by evidence left on their smartphones.